Dr Henrik Ehrsson, UCL Institute of Neurology ...the first experimental method to induce an out-of-body experience in healthy participants.
“The invention of this illusion is important because it reveals the basic mechanism that produces the feeling of being inside the physical body. This represents a significant advance because the experience of one’s own body as the centre of awareness is a fundamental aspect of self-consciousness.”
The set-up of the illusion is as follows: the study participant sits in a chair wearing a pair of head-mounted video displays. These have two small screens over each eye, which show a live film recorded by two video cameras placed beside each other two metres behind the participant’s head. The image from the left video camera is presented on the left-eye display and the image from the right camera on the right-eye display. The participant sees these as one ‘stereoscopic’ (3D) image, so they see their own back displayed from the perspective of someone sitting behind them.
The researcher then stands just beside the participant (in their view) and uses two plastic rods to simultaneously touch the participant’s actual chest out-of-view and the chest of the illusory body, moving this second rod towards where the illusory chest would be located, just below the camera’s view.
The participants confirmed that they had experienced sitting behind their physical body and looking at it from that location. Dr Ehrsson said: “This was a bizarre, fascinating experience for the participants – it felt absolutely real for them and was not scary. Many of them giggled and said ‘Wow, this is so weird!’”.